Malassezia may play a role in several dermatoses. It is responsible for foliculitis and mainly for pityriasis versicolor. Pityriasis versicolor is the most known dermatitis because of its clinical aspects and frequently for its poor response to the therapy, mainly in chronic forms. The clinical aspects of uncommon and rare forms of pityriasis versicolor have been reported. The data related to the patients observed in the last thirty years in Siena are reported. In addition, a study was carried out in Pisa by Professor F. Mancianti to identify species of Malassezia isolated in 37 patients.